The Los Angeles Family and Neighborhood Survey (L.A.FANS) is a new longitudinal study of adults, children, and 65 neighborhoods in Los Angeles County. L.A.FANS provides a unique opportunity to study important socioeconomic and health-related behaviors and outcomes among adults and elderly, with a particular focus on the effects of neighborhood social and physical environments. The first wave of the L.A. FANS (L.A.FANS-1) was completed in early January 2002. Wave 2 of the survey (L.A.FANS-2) will be fielded beginning in spring 2004. In this R03 application, we propose to conduct an interim tracking study (ITS) of Wave 1 adult respondents in 2003. The ITS will allow us to: (1) assess strategies for locating and recontacting adult respondents from L.A.FANS-1 and update contact information for respondents who are found in order to maximize recontact and response rates in Wave 2 and (2) analyze patterns of individual residential mobility and migration and of neighborhood turnover during the interval between L.A.FANS- 1 and the ITS, and investigate the determinants of attrition and nonresponse in the ITS. The results of this study will have an important impact on the design and success of LA.FANS-2. Data from L.A.FANS-1 and ITS will also be used to investigate the determinants of individual residential mobility and migration among adults and the elderly and the determinants of residential turnover in Los Angeles neighborhoods.